Differential mechanism



M y 9 F. M. LEWIS 2,555,044

DIFFERENTIAL MECHANISM Filed Sept. 1, 1948 2 Sheets-Sheet 1 &1

y 1951 F. M. LEWIS DIFFERENTIAL MECHANISM 2. Sheets-Sheet 2 Filed' Sept. 1, 1948 the respective wheel exceeds the torque =or ve driven membe g-ia;; flz ;g

Patented May 29, 1951 r r 2,555,044 BIFEEBEl-Y I E -3 4mm 'Frank M. iwisgmn t Clemens, Mich. Appli at Se ember 1, 1948, Sensing-41,27; J tnlblaiinsr (01. 7.41650) The differential mechanism of practically FigB-isanexploded wiewof the several ;.parts every motor d-river; vehicle; designed to permit go to :meik'e n p that portion of :the SPIKE:-

one drive wheel to'over-run the-other on curves,- ferregl form of difierential.showninliigs.fliandiili. presents'the problem of getting the "vehicle under The preferred embodiment, constructediirracway if one of the wheels has a ti'aotiori coni- K cordanoe-With*thisfinvention, comprises-ea gmain tion materially less tnan'that of thebtherWhel. driving member 1 and :ia' .pfililzbf driven members The well-known spirming of one of the wheels 8 and. 9. The latter are adapted to be operatively isian inevitable consequence. Variousattemfits connected with the former through thelmesiium have been made to overcome this difiionl ty'i-by of cliitoh 'elements li:.and :I l z-zwherewith-are asconstrudting'diiferentialswhich wo ild delivei' the 10 soeiatetl the disabling rings .12 and 1:3 which too"- driving power effectively to bbthvvheels ,yet allovl operate With" -the respect'me jolriven :membierswil for the imperative need-for either-of the Wheels and. 9 t0' disengage'iheaclutch elements Miami to over-run the other when-thevehicle-is ute- N from the respective. driven .members 8 and ing a curve. 'I-I'ov'vever,"'-it would 'appear' tl-iat, ll when the torqu'e'rror zvelocity of one ...of athe becanse'of'defects or-lirnitations inherent therein, driven members oanse'd :dzo .exceerl'w'the ztomue these prior -Const11ucfions have met with little or velocity of thewdriving :memhers .a'l.

or no success-assnbstitiitesiofithe stanlard t ype The main drivingimeni-ber i is roi "2, more 101 of differential mechanism with which motofless on ver-itional-construction. iAsherein' shown ciri-ven vehicles norm'ally are-equipped. 1 it comprises a pair of partsrlxl :and doetween The main o'jbjec't'so'f invention; therefore, whioh'iand lrotatahlymrranged :therewith Li's-a are to provide an" improv'e'd form ofdifferen'tial spider 116.

mechanism for use witn'motor-driven vehicles The parts Jdllan'd kii are securediheiraswhich will deliver the-power independently "to sern'bled"'relationshioby sets lof'ibolts and nuts each driving wheel but- -permit overrunrimg of I! and provide 5a 'ihousing'ior the v:o'ther thereineither'wheel when the "vehicle is rounding a before-described parts of the :meoh-anism. A

curve; to provide a di-ffierential of this klinl gear ls i s securedztmthe member-M with :Whichwherein the driving clutch element is :automeshes aqiinion 12(nntxshown) connected in the.

matieally helol retracted from driving relatio'nusual manner to the motor wehicle 'Leng-ine. ship with :either .of the .co-acting .zdriven olutch will be' noted from'nthe drawings the anembers elements so long *as the torque -.or vlocityof Mfand l 5 pro vide he'aring's L119 gandt-ZO for the lo'city of the driving member anfi lwhereinthe The driving-member pitler 426, :as .is :most clutch elements resume lnormal driving clearly shown=in' Eig. 6," has';a rhublsectionfflrel i nship wlhe he mq or' v lo y o h which isomer-posed between the :ends chf'ithe r p c iv whe l has :been overtaken by the driven members" 8 and 9, and 'held in :proper fiorpllovide B ld igl a fi rfi s 22. ut-'f-rom"-t1=iis hub seo tion extend a plurality so icconstruotedas to .zbernonvenientlysubstituted of radig l rm a i' pef-ve m wh ah tzb for the difierential tofnthe t-standard typewith tween t housing members M and I5, Eaohigf hi nr ti lhnal w the oomm mia mot 40 the arms, interiiretiiate' the 'hub*-and ,the outer driven vehicle o meesm pn d. endthereof is recessed to provide' a' pa'ir of 10am ll} t e lg llaw n f s'ur-faees "2'3 and' zd' whioh oo-Qact with comple- JEY E- 1S a vert oa :SQQJ H J vle 9 .11 13- n'ientarysurfaces on thewlutohaelements zlillia'nd e ed term o dif eren m phanism simmer-- 11 to ensure the"ldrivingfiengagement or said 111% iq fi m'fintmm 4 5 clutch elements-With the respective driven anem- 2 a re ucedrsqalei en fi tration b ers :a antl lkasvwill' appear zmore 21711115 hereinh im ve ,di eren a he is s i VQ after. l herecesses ifi are iilormed oncthezsnider irom t u ntin and driirl t mdu eg he. tin arrns merely for zthe tpurlpose" of roleara'nce aior and h0wing the pOsition Q Pa 1mm? the axial shiftingiof the clutohelements, l0 anol the normal driving of both tn Q H relative .totitheas'pider ;h6,:aswill ,be-setgforth her by .rt ed vi g -n emher;

iw 'mila izvir sh win the relation shipoftheseveral parts when the torque o eityo ne-o @wl venmm h to e or e o it o the .d

later.

in theiform of gears. Ilnzta'ctithesaa-re theggears constituting a standard :part .of the difierential menhanism regularly provided 'lfDI' gthe transport :F :4 s an en ar ed vffiti h Q. vehicle. As shown, these gears :are .:keyegi :to

of th e t por n ,o the iassembl. I shafts and :21 5,011 (the {ends -,of which are Fi mounted ':.the arear wheels (not shown) of the g. 5 is a vertical elevation @taken ton the line transpont vehicle.

5-5 ao'fsEig. 4:; :and 7 t0 lhe cclutch-elements Jill and 1,4 are in the torn).

The dnivenmemberslikandrfi'aredierein shown of annuli recessed at 28 on one side to fit the cam surfaces 23 and 24, and the recess 25 of the arms of the spider I6, and recessed on the other side at 29 (Fig. 4) to support the rings I2 and I3. The outer faces of theseclutch elements I8 and II are serrated to provide shallow teeth 38 capable of intermeshing with the teeth on the gears 8 and 9 to effect a driving relationship between the clutch elements I8 and II and the gears 8 and 9.

As will appear most clearly from Figs. 2 and 3 the recesses 28 are slightly larger than the recessed portions 23, 24, and 25 of the spider arms. This is to permit .both a slight axial and a slight rotative movement of the clutch elements relative to the spider I6 for reasons which will appear more fully hereinafter.

On their opposed faces the clutch elements I8 and II are provided with pairs of diametricallypositioned pins 3| and recesses 32 and recessed springs 33.

The pair of pins and apertures on the respective clutch elements I8 and II are so positioned that when the clutch elements I8 and II are assembled on the spider I6 the pins 3I on one element are received in the apertures 32 on the opposite element. The recesses 32 are slightly larger than the pins 3| to permit but ultimately check slight relative rotation of the two clutch elements. The springs 33 normally urge these elements I8 and II axially outward to cause the engagement of the teeth 38 with the teeth of the driven gears 8 and 9.

The annular recess 29 on the clutch elements I8 and II is formed in the perimetrical portion of these elements which is opposed to the respective driven members 8 and 9. As most clearly shown in Figs. 1 and 4 the recess 29 is formed so as to provide an annular radially-disposed shoulder 34 and an axially-disposed outwardlyinclined ledge 35 against and on which is supported a ring I2 or I3.

The rings I2 and I3 have the perimetrical portions opposed to the driven members 8 and 9 formed with alternate depressions 3B and projections 31 in the nature of gear teeth to fit the gear teeth 38 on the driven members 8 and 9.

The depressions 36 are of a depth and a shape to receive the ends of the teeth 38 on the driven members 8 and 9 when the clutch elements I8 and II have their teeth 38 in intermeshing relationship with the teeth on said driven gears 8 and 9.

The projections 31 on the rings I2 and I3, although not necessarily so, are here shown to be shallower than the depressions between the teeth 38 on the gears 8 and 9. As is most clearly shown in Figs. 2 and 3, these projections 31 have their sides recessed intermediate the base and the crown thereof so as to provide shoulders 39 on each side of each of said projections and which are very slightly inclined to the axial plane of the rings. The function of such specially-formed projections 31 will be fully set forth in a following statement of operation.

The inner annular parts of the rings I2 and I3 opposed to the ledges 35 on the clutch elements I8 and II are recessed to provide axiallydisposed inwardly-inclined surfaces 48. These surfaces are engaged by a plurality of taperedend pins 4I located in recesses 42 formed in the ring ledges 35, which pins are pressed by springs 43 into engagement with the inclined ring surfaces 48. By means of these spring-pressed pins M the rings I2 and I3 are retained in rotative relationship with the respective clutch elements l8 and II even when such clutch elements are removed from association with the other parts of the mechanism.

The operation of this differential mechanism is substantially as follows:

Through the usual pinion (not shown) power is applied to the gear I8 which is communicated to the spider I6. The springs 33 normally hold the teeth 38 on the clutch elements I8 and II in mesh with the teeth on the driven gears 8 and 9. On a straightway operation of the motor vehicle the torque of the spider is so presses the cam surfaces 23 or 24 (depending upon the direction of rotation of the pider IE) on the arms of the spider against the complementary cam surfaces formed by the recesses 28 that the clutch elements I8 and II are held in driving engagement with the driven gears 8 and 9. Thus the driving force of the spider I6 is equally and independently applied to the shafts 26 and 21, and regardless of their relative traction conditions the two wheels mounted on the shafts 26 and 21 have to turn. Under such conditions the teeth 38 on the driving gears 8 and 9 are lodged in the depressions 36 on the rings I2 and I3, as most clearly shown in Fig. 2.

In the event the motor vehicle rounds a curve the driving force of the spider IE will continue to be applied to the driven gear 8 or 9 for the inside wheel. The outside wheel will have its velocity accelerated over that of the inside wheel. As a consequence there will be a forward driving torque applied to the respective driven gear 8 or 9 greater than the torque of the spider I6. The resultant pressure of the teeth 38 on the gear 8 or 9 will have a camming action on the projections 31 below the shoulders 39 and move up onto the shoulders 39 with the result that the ring I2 01' I3 will exert a pressure on the corresponding clutch element I8 or II forcing it axially inward against the action of the springs 33. At the same time the ring and clutch element will be given a slight rotative movement relative to the spider I6. The inward axial movement of the clutch element I8 or II will cause a disengagement of the teeth 38 from the gear teeth 38 and effect a disengagement of the driving relationship of the clutch element I8 or I I and the respective driven gear 8 or 9. Such a relationship is shown in Fig. 3. This position of the parts will continue until the motor vehicle moves back into a straightway direction and the torque of the spider I6 again exceeds the torque of the erstwhile faster moving wheel.

When a clutch element I8 or II is thus forced axially inward its tendency toward rotative movement relative of the spider I8 is limited by the movement of the pins 3I in the recesses 32.

Variations and modifications in the details of structure and arrangement of the parts may be resorted to within the spirit and coverage of the appended claims.

I claim:

1. A differential mechanism of the class described comprising, a driving member, a pair of driven members, a pair of clutch elements mounted on said driving member for independent relative movement and rotation therewith but axially shiftable thereon into and out of driving engagement with the respective driven members, coacting means on said driving member and said clutch elements for limiting independent rotation of each of said clutch elements relative to said driving member and to each other coincident with the axial shifting thereof, yielding;

means normally urging said clutch elements into driving relationship with the respective driven members, a ring rotatably mounted on of said clutch elements in opposedarelationship to the respective driven members, and tic-acting cam surfaces on the opposed faces of said rings and driven members adapted to permit the en-.9

gagement of said :ciuteh elements with theirre-.

spective driven members when the torque oil-said driving member is uniform onbothoifrsaidclutch elements but cause-the axial sep'arati'cm of nne of said clutch elements and its driven memberative movement androtation therewith but axe ially shiftable thereon into and out of driving engagement with the respective driven members, co-acting means on said driving member and said clutch elements for limiting independent rotation of each of said clut h elements relative to said driving member and to-each-other 569L1 1 cident with the axial shifting thereof a ring rotatably mounted on each of said clutch elements in opposed relationship to the respective-airmen members, intermeshing projections on the-opposed faces ef said rings and driven members, the projections on each ring being recessed along their sides intermediate the crown and base thereof to form-shoulders on each side :ofreach of said ring projections, said projectionscosacting when the torque of one of said driven members exceeds the torque of said driving member to shift the opposed ring and its associated clutch element axially inward thereby causing a disengagement of the respective clutch element from said driven member and to permit said driven member projections to engage said ring-projection shoulders so as to hold said ring and associated driven member in its axially retracted position so long as the torque of said driven member exceeds the torque of said driving member.

3. A differential mechanism of the class described comprising, a driving member, a pair of driven members, a pair of clutch elements mount-,- ed on said driving member for independent relative movement and rotation therewith but axially shiftable thereon into and out of driving engagement with the respective driven members, co-acting means on said driving member and said clutch elements for limiting independent rotation of each of said clutch elements relative to said driving member and to each other coincident with the axial shifting thereof, springs normally urging said clutch elements into driving relationship with the respective driven members, a ring rotatably mounted on each of said clutch elements in opposed relationship to the respective driven members, intermeshing projections on the opposed faces of said rings and driven members, the projections on each ring being recessed along their sides intermediate the crown and base thereof to form shoulders on each side of each of said ring projections, said projections co-acting when the torque of one of said driven members exceeds the torque of said driving member to shift the opposed ring and its associated clutch element axially inward against the action of said springs thereby causing a disengagement of the respective clutch element from said driven member engage said ring-projection shoulders so as to holiisaid ring and associated driven member its axially retracted position so long as the torque of said driven member exceeds the torque of said driving member.

4. A lciiiierential mechanism of the class described comprisin a driving member, a pair of driven ears, pair of clutc l m n m nted on said {driving member-for independent relative movement and rotat n the w h u a all shiftabie thereon t and out o d in en a ement with the es cti e d iven g a s the faces of said clutch elements opposed to said gears bens se ated to orm te h int mes in i he teeth said:seara o-a tins artisan n S d mg mernb erand said clutch elements for limite ing melependent rotation of each of said clutch elements relative to said driving member and to ach other coincident th S d a i f in er f-j, y e d n means norma y u ing said clutch elements driving relationship with said respective driven gears, a ring rotatably mounted on each of :said clutch elements in opposed relationship to the respective driven gears, theper-imetrical portions of said rings opposed to the respective drivengears being formed with gear teeth adapted to mesh with said driven gears,.-said ring gear teeth being recessed along their sides intermediate the crown and the base thereof to term shoulders on .eachside .of each ,of said gear teeth, the teeth on said driven gears co-acting with the teeth on said rings when the torque of one of said driven gears exceeds the torqueaof said driving member to shift the op,- posed ring andits associated clutch element axially inward thereby causing a disengagement of the respective clutch element from said driven gear and to permit said driven-gear teeth to engage said ring-teeth shoulders so as to hold said ring and associated driven member in its axially shifted position so long as the torque of said driven gear exceeds the torque of said driving member.

5. A differential mechanism of the class described comprising, a driving member, a pair of driven members, a pair of clutch elements mounted on said driving member for independent relative movement and rotation therewith but axially shiftable thereon into and out of driving engagement with the respective driven members, co-actin means on said driving member and said clutch elements for limiting independent rotation of each of said clutch elements relative to said driving member and to each other coincident with the axial shifting thereof, yielding means normally urging said clutch elements into driving relationship with the respective driven members, said clutch elements having annular recesses formed on their perimetrical portions opposed to said driven members, a ring rotatably mounted in the annular recess of each of said clutch elements, and co-acting cam surfaces on the opposed faces of said rings and driven members adapted to permit the engagement of said clutch elements with their respective driven members when the torque of said driving member is uniform on both of said clutch elements but cause the axial separation of one of said clutch elements and its driven member when and so long as the torque on the respective driven member exceeds the torque of said driving member.

6. A differential mechanism of the class described comprising, a driving member, a pair of driven members, a pair of clutch elements 7 mounted on said driving member for independent relative movement and rotation therewith but axially shiftable thereon into and out of driving engagement with the respective driven members, co-acting means on said driving member and said clutch elements for limiting independent rotation of each of said clutch elements relative to said driving member and to each other coincident with the axial shifting thereof, yielding means normally urging said clutch elements into driving relationship with the respective driven members, said clutch elements having annular recesses formed on their perimetrical portions opposed to said driven members, a ring rotatably mounted in the annular recess of each of said clutch elements, the inner face of each of said rings being annularly recessed to provide an axially-disposed inwardly-inclined surface, radially-disposed spring-pressed pins located in sockets in each of said rings with the outer ends of said pins tapered to engage said inclined surfaces on said rings and thereby hold said rings against displacement on said clutch elements and co-acting cam surfaces on the opposed faces of said rings and driven members adapted to permit the engagement of said clutch elements with their respective driven members when the torque of said driving member is uniform on both of said clutch elements but cause the axial separation of one of said clutch elements and its driven member when and so long as the torque on the respective driven member exceeds the torque of said driving member.

7. A differential mechanism of the class described comprising, a driving member, a pair of driven members, a pair of clutch elements mounted on said driving member for independ ent relative movement and rotation therewith but axially shiftable thereon into and out of driving engagement with the respective driven members, co-acting means on said driving member and said clutch elements for limiting independent rotation of each of said clutch elements relative to said driving member and to each other coincident with the axial shifting thereof, a ring rotatably mounted on each of said clutch elements in opposed relationship to the respective driven members, and co-acting cam surfaces on the opposed faces of said rings and driven members adapted to permit the engagement of said clutch elements with their respective driven members when the torque of said driving member is uniform on both of said clutch elements but cause the axial separation of one of said clutch elements and its driven member when and so long, as the torque on the respective driven memberexceeds the torque of said drivin member.

FRANK M. LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

